1. The Field of the Invention
This invention relates to aircraft control systems and, more particularly, to novel systems and methods for cockpit control levers for pitch and roll.
2. The Background Art
Aircraft move in several degrees of freedom. An aircraft can translate vertically, forward and backward, or side-to-side. Similarly, an aircraft can change orientation by rolling about a longitudinal axis, by pitching about a side-to-side axis, or yawing about a vertical axis through the center of gravity, or any other vertical axis. Thus, an aircraft may rise or drop, move forward or backward, move right or left, or rotate about a roll axis, pitch axis, or yaw axis.
In order to control an aircraft, one must know what type of aircraft is to be controlled. For example, some aircraft have a fixed wing. Other aircraft have a rotary wing. In rotary wing aircraft, some have power driving the rotary wing. Others have no power to the rotary wing. Similarly, an aircraft has control surfaces, such as ailerons, elevators, rudders, and so forth in order to orient the aircraft, and otherwise direct the aircraft to move in one of the available degrees of freedom.
Meanwhile, aircraft, whether fixed wing, helicopter, auto-gyro, or other variety, have some type of motive system such as an engine, propeller, combustion jet, or the like to drive the aircraft forward. Propellers or jets may provide forward thrust, a surface of an airfoil may provide lift, and various control surfaces may provide differentials in lift or load on a portion of an aircraft in order to rotate or translate all or part of the aircraft.
Typical controls for an aircraft include a throttle, as well as propeller, pitch angle, and the like for controlling the rate of advance of an aircraft in a forward direction. Similarly, ailerons may affect the roll of an aircraft. Typically, an elevator affects the pitch angle, while the rudder affects the yaw angle of an aircraft.
In rotor craft, control systems may be somewhat more complicated. Nevertheless, the same degrees of freedom apply. However, in a helicopter, for example, yaw is controlled by a tail rotor. Pitch is controlled to some extent by an airfoil in certain rotor craft, but is also controlled by the relationship between the rotor head and the fuselage of the aircraft. Similarly, whereas a fixed wing aircraft can roll by use of aileron positions, a rotor craft typically moves in a roll direction to some limited extent only, and then by affecting the angle between a rotor blade, or rotor head, sometimes defined in terms of a rotor disk, or the like, and the fuselage of the aircraft.
In aircraft control, a ubiquitous structure for pilot control of various aspects of an aircraft has been the stick. The stick is so ubiquitous as to be used in control systems for video games and other venues where multiple degrees of freedom may be called for simultaneously. One advantage of the conventional aircraft control stick is the ability to affect roll and pitch from a single control member simultaneously.
For example, pulling back on a stick (which typically pivots near the floor or some other mounting surface for the stick) effects a pitch angle, increasing the elevation of the nose with respect to the tail. Pushing a stick forward, pivoting the handle of the stick forward results in a nose down attitude tending to move the nose down with respect to the tail. In a fixed wing aircraft, forward and backward motion of the control stick typically operates on an elevator control surface in the tail of the aircraft.
Similarly, pivoting a stick to the left or right tends to roll an aircraft. In a fixed wing aircraft, tilting the stick to the left or right affects the positions of ailerons in the main wing surfaces. In a rotor craft, moving a stick control right or left typically affects the relative position of a fuselage with respect to a rotary wing. Thus, left to right typically controls roll angle, while forward and backward affects pitch angle of an aircraft.
Forward speed is typically controlled by a throttle and a propeller angle in a fixed wing aircraft, and by a combination of throttle and tilt of a rotor blade in a helicopter. Forward speed in an auto-gyro is controlled by a throttle setting to an engine, and the angle of pitch of the propeller, if properly driven, and the thrust of a jet, if jet driven.
Many aircraft have dual seating for pilot and co-pilot. Some aircraft may seat a pilot and copilot in tandem, one behind the other. Nevertheless, most aircraft seat a pilot and co-pilot side by side in a dual configuration. In a dual seating arrangement, both pilot and co-pilot have access to many or all of the same instruments. However, access to the same controls has been addressed in various ways. Many aircraft have dual control systems. For example, large, commercial, fixed-wing aircraft typically have two fill sets of controls, one in front of the pilot, another in front of the co-pilot.
In small aircraft, duplicating controls adds additional weight, complexity, additional parts to wear, and so forth. Moreover, in many smaller aircraft, a pilot and co-pilot sit shoulder-to-shoulder. Thus, access to instruments and many controls on a control panel may be readily available. However, typically, hand controls, such as the stick, can hardly be shared. The pilot or co-pilot needs a control stick in a particular location, preferably centered exactly in front of the individual. Duplicating controls can present several problems. For example, duplicate control sets may cause a difficulty if one of the persons in the seat beside a pilot is not a co-pilot. Having an extra control system to be bumped by a passenger is unsafe. Moreover, having a dual system of controls in front of a passenger can also be a waste of space. Moreover, having controls in front of a passenger creates problems for the passenger doing other activities. Thus, it would be desirable to have a system of controls that can be made optionally available to a pilot and co-pilot team, or a trainer and trainee, and yet stowed away when only a single flight-qualified operator is available or otherwise present.
What is needed is a control system that is readily deployable for use by either a pilot or copilot, and yet which has a configuration in which stowing the actuators dedicated to one person in a set of dual seats removes any difficulty of obstruction, safety, inappropriate or accidental actuation, or the like from the non-flight-qualified passenger.
What is needed is a fold-up system for aircraft stick controls to selectively render the control system readily accessible to a co-pilot, but stowed in a non-obstructing manner, safely for situations where a passenger occupies the second seat in a dual seating system.
It is an object of the invention to provide an aircraft stick control system that can readily adapt to use by either a pilot or co-pilot. In certain embodiments, it is an object of the invention to provide selectively deployable control actuation for a pilot and co-pilot in a dual-seating arrangement.
Consistent with the foregoing objects, and in accordance with the invention as embodied and broadly described herein, an apparatus and method are disclosed, in suitable detail to enable one of ordinary skill in the art to make and use the invention. In certain embodiments an apparatus and method in accordance with the present invention including an upright mounted to an aircraft to move in directions corresponding to control of pitch and roll of an aircraft. In general, the apparatus may have movements in a longitudinal and lateral direction, as well as a transverse direction, where all directions are substantially orthogonal to one another. The apparatus may include yokes, pins, brackets, links, clevises, or other fastening means to connect to cables, links, electrical controls, or other devices for effecting pitch and roll control of an aircraft.
In certain embodiments, the apparatus may include a receiver, for holding or adjusting an upright, at a lower end thereof, with a head positioned on an upper end thereof. The head, or the upright directly, may support one or more cross beams. In certain presently preferred embodiments, at least one cross beam extends laterally in front of a pilot, while another extends from an upper end of the upright, or a head connected to an upright, in the opposite direction, to be positioned in front of a co-pilot.
The head, or the upper end of an upright directly may include clevises, yokes, pins, or other fastening mechanisms and pivot systems in order to connect the cross beams to the upright while maintaining certain degrees of freedom, and while failing to maintain (restricting) other degrees of freedom relative to one another. In one embodiment, a handle may fit at one end of a cross beam in front of an operator (pilot, co-pilot, etc.), with another at the opposite end of another cross beam, in front of another aircraft operator.
The cross beams preferably pivot independently from one another in order to stow down (or optionally up) beside the upright, the handle being positioned near the anchor (e.g. lower) end of the upright, and the control system being unavailable to an operator (e.g. co-pilot) on that corresponding side of the upright. Meanwhile, the cross beam may be pivoted at one end out away from the upper end or head of the upright, with the opposite end of the cross beam pivotally connected to the head or upper end of the upright.
In certain preferred embodiments, a handle may extend upwardly or downwardly from a distal end of a cross beam. Also, the upright may extend up from a floor or down from a ceiling. Thus, mirror image configurations with handles pointing up or down are contemplated. A cross beam may be pivoted such that the handle is bound to move in rigid body motion with respect to the upright in a pitch-control direction. Meanwhile, the handle may pivot with respect to the cross beam, or not pivot with respect to the cross beam, in a roll-control position. Nevertheless, in a roll-control position, the cross beam will pivot with respect to the upright, in order to maintain a clearance and prevent interference between the person of an operator, and the cross beam with its associated handle.
In some embodiments, a handle may have a grip for more easily engaging the fingers of a user against slipping from the handle. To this end, a hilt may also be part of a handle. In some embodiments, a hilt and retainer may sit at opposite ends of a handle, in order to provide more positive engagement between a hand of a user, and the handle.
A handle may connect to the cross beam by a bracket. The bracket may pivot on a shaft, or may be fixed to move rigidly with respect to the cross beam. In certain embodiments, brackets may rotate on shafts or journals in order to angle as needed to more comfortably engage a right or left hand of a user. Since pivoting a handle about its own approximately vertical axis, such relative motion may be desirable. Nevertheless, some individuals may feel more comfortable having more rigidity in the control, and thus a more direct feel for the position of the upright, which fills the position largely of a conventional stick in an aircraft.
Nevertheless, the upright is positioned near the center between the seats of two operators. By contrast, a conventional stick would be mounted directly in front of, and centered on the seat of each operator.
In certain embodiments, a single cross beam may be replaced by a pair of cross beams. For example, a parallelogram formed by two cross beams pinned to the upright, or a head on an upright, may close at a distal end with a link pivotably pinned to parallel the upright, but at an opposite end of the twin cross beams. Accordingly, an orientation of the handle fixed to the link may effectively replicate the angle, or some relationship with the angle of the upright in a roll-control position. In one presently preferred embodiment, pins may extend essentially forward through cross beams, in order to provide a degree of freedom of the cross beams to move in a plane through the upright in all pitch-control attitudes.
Meanwhile, the parallelogram structure may permit positioning of a handle in substantially any vertical height, with respect to an end of the upright, with only modest change in the side-to-side positioning of the handle. That is, a parallelogram could be collapsed against the upright, stowing the handle parallel thereto, with the parallelogram cross beams also parallel to the upright. Meanwhile, a handle can be moved for deployment away from the upright, remaining parallel thereto. Upon deployment, the handle may be drawn away from the upright, typically from a position near a lower end thereof, remaining parallel thereto, while the parallel cross beam pivot from a stowed orientation substantially parallel to the upright, and out of the way of a user, out to a substantially horizontal, laterally extending position supporting the handle directly in front of a user.